Chronic exposure to metal fume PM_2.5 on inflammation and stress hormone cortisol in shipyard workers: A repeat measurement study

Particulate matter with an aerodynamic diameter of ≤ 2.5 µm (PM2.5) has been linked to adverse health outcomes in welding workers. The objective of this study was to investigate associations of chronic exposure to metal fume PM2.5 in shipyard workers with health outcomes. A longitudinal study was conducted to determine the effects of metal fume PM2.5 on FeNO, urinary metals, urinary oxidative stress, inflammation, and stress hormones in workers. There were 20 office workers and 49 welding workers enrolled in this study who were followed-up for a second year. We observed that Fe, Zn, and Mn were abundant in PM2.5 to which welding workers were personally exposed, whereas PM2.5 to which office workers were personally exposed was dominated by Pb, Cu, and Zn. We observed in the first and/or second visits that urinary 8-iso-prostaglandin F2-α (PGF2α) and 8-hydroxy-2′-deoxy guanosine (8-OHdG) were significantly increased by exposure. An increase in urinary interleukin (IL)-6 and decreases in urinary serotonin and cortisol were observed in the first and/or second visits after exposure. PM2.5 was associated with decreases in urinary 8-OHdG and cortisol among workers. Next, we observed that urinary Ni, Co, and Fe had significantly increased among workers after a year of exposure. Urinary metals were associated with decreases in urinary 8-iso-PGF2α and cortisol among workers. Urinary Ni, Cu, and Fe levels were associated with an increase in urinary IL-6 and a decrease in urinary cortisol among workers. In conclusion, chronic exposure to metal fume PM2.5 was associated with inflammation and a cortisol deficiency in shipyard workers, which could associate with adrenal glands dysfunction.